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March 24, 1964 R. s. LANIER ETAL ROTARY FLUID DISPLACEMENT DEVICE 4 Sheets-Sheet 1 Filed June 6, 1961 INVENTORS pi q 7. 77 m BY Val/"MW:

March 24, 1964 R. s. LANlER ETAL ROTARY FLUID DISPLACEMENT DEVICE 4 Sheets-Sheet 2 Filed June 6, 1961 IN VEN TORS R. s. LANlER ETAL 3,125,962

ROTARY FLUID DISPLACEMENT DEVICE 4 Sheets-Sheet 3 March 24, 1964 Filed June 6. 1961 96 Inventors 5 Tia/Magi M r 1964 R. s. LANIER ETAL ROTARY FLUID DISPLACEMENT DEVICE 4 Sheets-Sheet 4 Filed June 6, 1961 ug w 1&1 14

United States Patent 3,125,962 ROTARY FLUID DISPLACEMENT DEVICE Reginald S. Lanier, Minneapolis, Minn, and Wolf F.

Muller, New York, N.Y., assignors to Washington Scientific Industries, Inc., Minneapolis, Minn, a corp0 ration of Minnesota Filed June 6, 1961, Ser. No. 115,146 8 Claims. (Cl. 103-140) The present invention relates to an improved rotary fluid displacement device effective in pumping or motor action to displace a predetermined quantity of fluid (such as oil) for each shaft rotation.

Rotary type fluid displacement devices provide theorically large pump or motor horsepower in relation to machine size. In practice, however, such devices have re ceived only limited use up to the present time. Practical considerations such as excessive bearing load requiremen-ts, short bearing life, intolerable noise, unacceptable efiiciency, and excessive overall costs have largely prevented attainment of the theoretical advantages of these devices.

In accordance with the present invention, an improved fluid displacement device is provided in which many of the problems heretofore associated with such fluid displacement devices are overcome. In brief, the device of in the circumferential position each vane nests within the confines of the sleeve l-ike rotor. A pair of shoes affixed to the housing form fluid seal surfaces in relation to the rotor sleeve. These are located in diametrically opposed relation to the working portion of the cavity and are of sufficient circumferential extent to define sealing surfaces on opposite sides of the rotor windows. Fluid inlet and outlet passages are located on opposite sides of the shoes. The unit is closed by end cap elements incorporating the drive :or driven shaft.

In operation, for example as a pump, the drive shaft is turned, thereby rotating the sleeve-like rotor. As the rotor is thus rotated, the respective vanes are rotate-d in relation to the rotor to assume a circumferential orientation nesting within the rotor sleeve to pass between the shoes. At the diametrically opposed working portion of the housing, the vanes are respectively turned to the radially oriented positions. Rotation of the shaft, and rotor, therefore results in each vane becoming effective to obstruct the working portion of the cavity in the housing as it traverses that portion of the cavity. The fluid is accordingly driven in the direction of the vane movement, and hence from the inlet passage to the outlet passage. The resulting pump action serves to pump the liquid from the inlet to the outlet passage. LP or operation as a motor, the fluid supplied under pressure in the inlet passage serves to bear against each of the vanes when in radial orientation (in the working portion of the cavity), thereby developing torque tending to rotate the shaft.

A crank and cam mechanism orients each vane as required for motor or pump operation. -In the preferred form each vane shaft extends through the sleeve-like rotor at one end and terminates in a crank arm, to which is affixed a cam follower extending outboard the crank arm. The respective cam followers ride in a single groove formed in the face of a cam plate. The latter forms part of the closure for the open side of the annular opening in the housing. A single cam groove extends about the orbit of travel of each vane and is of varying radial distance from the center line of the shaft as necessary to rock the Ice respective vanes to radial or circumferential positions as required. Through the medium of the single cam groove the respective vanes are swung degrees in relation to the rotor from the radial to the circumferential position in passing from the downstream end of the working portion of the cavity to the region of the shoes. They are returned to original radial position in relation to the rotor by an equal turn in relation to the rotor in the opposite direction as the vanes pass from the region of the shoes to the upstream side of the working portion of the cavity. In an actual device constructed in accordance with the preferred form of the present invention, it was found possible to operate up to the limit of available drive capacity and pump capacity without undue slap or other noise that might indicate that the limit of vane operation was being approached.

The device of the present invention is characterized by relatively modest bearing requirements. The rotor vanes, While they are required to rock during motor or pump operation, are not subject to such movements while under unbalanced fluid pressures. That is, the vanes are stationary in relation to the rotor during the time that they are in the radially oriented position and passing through the working chamber. It is thus possible to use relatively simple bearings for the vanes without undue wear or unduly short life. In the preferred form of the invention herein described in detail it was possible to secure effec tive operation with simple bronze sleeve bearings for the respective vanes. The device of the present invention is further characterized by effective operation at low noise levels. In the preferred form of the invention herein described, for example, no noise-producing gears are used, there is no metal-to metal rolling contact (other than relatively light contact required for the cam mechanism), and there is no slapping action of any of the parts. The device of the present invention additionally provides a favorable sealing environment. Resilient non-metallic sealing materials, such as Teflon, can be used even though they are not capable of withstanding fluid pressure differentials unless otherwise supported. The device of the present invention accommodates itself to such support by providing strong metallic supporting parts between which such sealing elements are sandwiched.

The device of the present invention is further character- 'ized by effective and simple sealing action. This is accomplished through the medium of the stator shoe elements which extend to sealing relation with the interior and exterior faces of the -sleeveike rotor. These shoe elements are of sufficient circumferential extent to span each rotor window. This assures that seal is made on the leading edge of each rotor window while the window is travelling into the space between the shoes and on the trailing edge of each rotor window while the window is travelling out of the space between the shoes. The seal so effected is similar to an air lock an-dsince it is made through the medium of arcuate inner and outer mating surfaces-can be formed by standard machine technique to provide a fully effective seal.

It is therefore a general object of the present invention to provide an improved fluid displacement device wherein vane elements assume fixed radial orientations during the working portion of each rotor rotation.

Another object of the present invention is to provide a fluid displacement device wherein a sleeve-like rotor has a plurality of vane elements which assume radial positions for working stroke and nesting circumferential positions for passage through the fixed shoes, these vane movements being attained through the medium of simple crank arm and cam mechanism.

Still another object of the present invention is to provide an improved fluid displacement device of the foregoing type in which the effective seals may be provided through the use of a relatively flexible material which is supported in sandwich action to provide effective seal through the use of materials otherwise unable to withstand the fluid pressures.

Another object of the present invention is to provide an improved fluid displacement device useful as a pump or motor which displaces a uniform quantity of fluid on each rotor rotation without periodic variations in fluid displacement, and hence without torque or fluid flow pulsations or any tendency to impart repetitive accelerations or decelerations to the moving fluid.

Still another object of the present invention is to provide an improved fluid displacement device useful as a pump or motor in which the fluid follows a U-shaped path having essentially tangential inlet and outlet passages in relation to a generally semi-circular working chamber, thus providing minimum turbulence and fluid energy losses, and in which the fluid is not required to travel through valves, orifices, or sharply curved channels.

Still another object of the present invention is to provide an improved fluid displacement device in which a windowed sleeve-like rotor passes between sealing shoes defining seals spanning the respective windows and in which the rotor vanes tuck into the rotor to pass between the shoes.

Yet another object of the present invention is to provide an improved fluid displacement device of the above type in which the sealing shoes are provided with spaced seal elements so positioned that they coact with the sleevelike rotor to effect sealing action without substantial leakage.

Another object of the present invention is to provide an improved fluid displacement device that embodies features of construction combination and arrangement making it particularly suitable for the practical use as a motor, or pump where large horsepower requirements must be accommodated in a small space, large shaft torques must be produced, and wherein the demands of long life, quiet operation, and efficiency are severe.

Still another object of the present invention is to provide an improved vane structure for use in a fluid displacement device.

It is yet another object of the present invention to provide an improved fluid displacement device wherein deformable fluid seals may be employed and wherein all such seals may be supported from the metal parts in sandwich relation providing firm support therefor.

The novel features which we believe to be characteristic of the present invention are set forth with particularity in the appended claims. My invention itself, how ever, both as to its structure and mode of operation, together with further objects and advatnages thereof, will best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a view of axial cross-section with parts in elevation of an illustrative fluid displacement device constructed in accordance with the present invention;

FIGURES 2 and 3 are cross-sectional views through axes 2-4. and 3-3, respectively, FIGURE 1;

FIGURE 4 is an enlarged and somewhat diagramiatic View like FIGURE 2 but showing in more detail the successive positions of the vanes;

FIGURE 5 is a view in perspective of the main housing bl ck and drive shaft housing block of the device of FIGURES 1-4, inclusive, when the same are folded out from each other;

FIGURE 6 is a greatly enlarged side elevation view with parts in section of the vane mechanism of the device of FIGURES 15, inclusive;

FIGURE 7 is a cross-sectional view through axis 7-7, FIGURE 6;

FIGURE 8 is a view of the vane structure in perspective;

FIGURE 9 is a view in perspective of the seal plate used with the vane of FIGURES 6-8, inclusive;

FIGURE 10 is a partially exploded view in perspective of a modified form of the rotor vane element of the device of the present invention;

FIGURE 10:: is a greatly enlarged fragmentary crosssectional View of a seal element of the structure of FIG- URE 10;

FIGURE 11 is a view in side elevation like FIGURE 6 but of the rotor vane element of FIGURE 10;

FIGURE 12 is a fragmentary view like FIGURE 1 but enlarged and showing a modified form of the rotor bearing support and seal construction;

FIGURE 13 is a view in perspective showing the housing of the fluid displacement device with an alternative form of the shoe elements which incorporate resilient seal elements; and

FIGURE 14 is a view in perspective of the rotor element (with inner end plate removed) of the fluid displacement device with the modified form of the vanes of FIGURES 10 and 11.

FIGURE 15 is a greatly enlarged fragmentary view similar to FIGURE 1 but showing the shoe construction of FIGURE 13 broken away to display the seals on the shoes.

General Description The general arrangement of the fluid displacement device will best be understood by reference to FIGURE 2, which is a cross-sectional view through axis 22, FIG- URE 1. As shown in FIGURE 2, an operating chamber or cavity 10 is formed in the main housing block 12. This chamber is of generally annular conformation about axis 1414, FIGURE 1. As seen best in FIGURE 2, the cavity 10 has a portion spanning essentially degrees of periphery, indicated by B, FIGURE 2, where the inner face or surface 16 and the outer face or surface 18 are of uniform annular spacing in relation to the axis 14. This portion of the cavity defines the power producing working chamber where fluid seal is established between each vane and the inner and outer faces of the cavity 10.

In diametral opposition to the working chamber portion B of cavity 10 there are a pair of complementary shoes 20 and 22. The former extends outwardly from the central post 17. The latter extends inwardly from the portion 21 of housing 12. Shoes 20 and 22 form sealing surfaces in relation to the rotor 24 as hereinafter described.

The rotor 24 is of sleeve-like conformation and is mounted for rotation about the axis 1414, FIGURE 1, as hereinafter described in detail. The rotor has a plurality of windows 26a, 26b, and 260. These respectively receive the vanes 28a, 28b, and 28c. As hereinafter described, each vane is mounted to swing about an axis parallel to the rotor axis 1414, FIGURE 1. As shown by the vanes 28a and 2812, FIGURE 2, these vanes are of sufficient length in their greatest dimension to form fluid seals across the annular or working portion B of the cavity It As shown by vane 280, FIGURE 2, the vanes are adapted when in the circumferential position to fall within the confines of the sleeve defined by the rotor 24 and hence to nest within the rotor to travel between the shoes 29 and 22 without mechanical interference, as shown.

FIGURE 8 shows one of the vanes in perspective. As shown, each vane is of rectangular shape as seen in plan. The axial length of each vane, as shown in FIG- URE 1, is sufficient to span the working chamber portion B (FIGURE 2) in fluid seal contact. The sealing action of the vanes is described in further detail hereafter.

Fluid is admitted to the operating chamber or cavity 16 through the inlet passage 30, FIGURE 2. It will be observed that this inlet passage is oriented in substantially tangential relation to the annular cavity and is located on one side of the complementary shoes 20 and 22. At 32 the outer face of cavity 10 is somewhat enlarged to provide fluid travel about a vane in this position. The outlet passage is indicated at 34 and, as shown, is parallel to the inlet passage 30. The outlet passage 34 similarly substantially forms a tangent to the annular cavity 19. The outer face of cavity 10 is relieved at 40 to permit fluid escape about the vane.

As shown in dotted form at 36 and 38, suitable fluid inlet and outlet pipes are received in the housing block 12. These supply fluid to and remove fluid from the inlet and outlet passages 30 and 34, respectively.

The inner shoe 20 extends a suficient distance in the outward direction to form a fluid seal in relation tothe inner face 23 of rotor 24. It will be noted that the shoe 2t) defines sealing spaces in relation to the inner rotor face 23 that are sufliciently spaced to span the Window 26c in which the vane 280 is located. Thus, as the rotor 24 rotates, there is always at least one fluid seal between the rotor 24 and the shoes 20 and 22, irrespective of the particular rotor position. As hereinafter described, this assures that the only path for fluid travel between passages 30 and 34 is through the working chamber portion B of the cavity 10. Similarly, the shoe 22 extends a sufficient distance inwardly to form a fluid seal in relation to the outer face 25 of rotor 24. This seal is of sufficient circumferential extent to span the window 26c as shown.

Practical Operation The practical operation of the fluid displacement device will now be described in relation to FIGURE 2 and to clockwise rotor rotation as illustrated in that figure. As the rotor rotates, the vanes 28a, 28b, and 28c, are successively oriented to the radial or active position as they commence the working stroke B. In FIGURE 2 the vane 28a is shown in working or radial position. At this time, fluid from the inlet passage 30 exerts its pressure upon the trailing face of the vane. Fluid leakage about the vane is small. The resultant force on the vane defines a moment in coaction with the rotor bearing support to drive the rotor in the clockwise direction as shown in FIGURE 2. The rotor 24 experiences no counter-torque since the shoes 20 and 22 are anchored to the stator.

As the rotor 24 turns in response to the above torque, the vane in working position remains in fixed radial orientation with respect to the rotor. This condition prevails for the full working stroke B which, in the form of the device as shown, is essentially 120 degrees. As elsewhere discussed herein, the bearings supporting the vane are accordingly not subject to vane movement at the time the fluid force is effective on the vane. During this working stroke of each vane, the vane immediately trailing the workng vane travels from the posiition of vane 280, FIGURE 2where it is between shoes 20 and 22-to the position to start working stroke B. During this time the trailing vane is swung from circumferential position (as shown at 280, FIGURE 2) to the sealing, radial, position (as shown at 28a, FIGURE 2), where it is conditioned for the working stroke.

While each vane undergoes the working stroke, the immediately leading vane (shown as 28b, FIGURE 2) travels from the terminal position of the working stroke B to the position of the shoes 20 and 22. The relief 40 and the increased size of chamber 10 permit fluid to travel about the vane and equalize the fluid pressure. This relieves the bearing load. The vane is swung in relation to the rotor to assume the circumferential or nested position within the confines of the rotor sleeve by the time it reaches the shoes 20 and 22 (and the position of vane 280, FIGURE 2).

The shoes 20 and 22, as described above, span the circumferential extent of the windows 26a, 26b, and 26c.

Accordingly, at least one margin or the other margin of the shoes is in sealing relation to rotor 24. Regardless of the rotor position, therefore, the fluid is restrained from passing from inlet passage 30 to outlet passage 34 through the space between shoes 20 and 22. Accordingly, the fluid travel from inlet passage 30 to outlet passage 34 is solely by way of the U-shaped path including inlet passage 30, the working chamber B, and the outlet passage 34. Since the fluid travelling through this passage is effective todo work on the rotor, all of the fluid flow through the unit is effectively used to produce mechanical Work.

In the above description, the unit is described as operating as a motor, that is, as a device to produce mechanical work from the fluid flow. If the rotor is mechanically driven, the action is as a pump-serving to convert the mechanical drive energy to energy of the fluid under pressure. With the rotor turning in clockwise direction as shown in arrow 43, FIGURE 2, the fluid flow as sociated with pumping action is as shown by arrows of the figure. Passage 3t) is the inlet passage and passage 34 is the outlet passage.

The rotor 24 may rotate in the counter-clockwise direction if desired. In such instance the fluid flows will be opposite to the arrows of FIGURE 2 whether motor or pump operation is involved.

The vane movements are described in detail hereafter. It should be noted that each vane swings degrees in relation to the rotor to rotate from the radial to the circumferential position and then swings back 90 degrees in the opposite direction from the latter position to the former.

Detailed .Mechanical Construction The detailed mechanical construction of the fluid dis placement device can best be understood by reference to FIGURE 1 taken in conjunction with FIGURE 2. As shown, the housing block 12 is closed at the left hand end 12a (except for the central oil-leakage bore 47). The housing is open at cavity 10 at the opposite end. The rotor sleeve element 24 has inner and outer flanges 44 and 46, respectively, at its left end as seen in FIGURE 1. These flanges terminate at the outer cylindrical or sleeve bearing surface 46a and the inner cylindrical or sleeve bearing surface 44a, FIGURE 1. These surfaces form sleeve bearings in relation to the corresponding inner and outer cylindrical surfaces 12b and 120, respectively, of housing block 12 to hold the rotor 24 in centered relation for rotation about axis 1414.

At the right hand end of the rotor 24', as seen in FIG- URE 1, the rotor has an inner flange 48 and an outer flange 50. These define inner and outer bearing surfaces 48a and 50a, respectively, which ride on cylindrical housing faces 12d and 120, respectively. It will be observed that the seal between faces 12d and 48a and the seal between faces 12c and 50a close the rig-ht hand side of the cavity 10, preventing substantial fluid escape in the axial direction from the device.

The rotor 24 is in floating axial position. That is, there is no unbalanced fluid pressure tending to force the rotor in either axial direction. The rotor is sealed on the right hand side as seen in FIGURE 1 by the seal effected by the Teflon seal 49 acting on cylindrical surface 48a and Teflon seal 52 acting on the inner cylindrical surface 120. On the left hand side the rotor is sealed by the Teflon seals 51 and 53 acting on cylindrical surfaces 12c and 12b, respectively.

The space to the left of the seals 51 and 53 is maintained at low pressure by the escape passage 55. The space to the right of the seals 49 and 52; is maintained at like pressure by one or more holes extending through the rotor sleeve portion, such as 57, FIGURE 2. As shown by the dashed lines of FIGURE 1, this passage permits free fluid communication between the opposed end faces of the rotor. Since the projected end area on 7 each rotor face is the same, equalization of this pressure avoids any axial fluid force on the rotor.

The rotor 24 is located in operating axial position by the flange portions 44 and 46, on the left side and the flange portions 48 and St) on the right side. The outer fiange portions 46 and t} straddle the outer shoe 22. The inner flange portions 44 and 48 straddle the inner shoe 20. In each instance the shoes and the flange portions define fiat faces that have working clearance preventing oil leakage between the inlet 30' and the outlet 34 while permitting the rotor to turn relatively freely. If desired, these shoes may be provided with seal elements as described hereafter in relation to FIGURE -13. As is described hereafter, the rotor is not directly coupled to the drive shaft 54, and thus is not subjected to any skewing or turn that might tend to bind the rotor in relation to the side surfaces of the shoes and 22.

As shown in FIGURE 1, the right hand outer flange shoulder 50 on the rotor is circurnferentially grooved and receives the seal ring 52 to prevent fluid escape from the working chamber. This ring is preferably of Teflon or similar material.

The Drive Shaft Arrangement The drive shaft (which may be either an input shaft or an output shaft) is indicated at 54, FIGURE 1. It is supported from the housing 58 by spaced ball bearings 56. This housing is mounted on the housing block -12 through the medium of annular lip 58a which is received tightly in a corresponding annular recess 12 in the housing block 12. The shaft 54 extends outboard on the right hand side of housing 58 to receive a suitable gear, pulley, etc. (not shown) to drive or be driven by the shaft 54. At its left hand end as seen in FIGURE 1, the shaft 54 terminates in a hub 60. This hub is shown in perspective view in FIGURE 5 and cross section in FIGURE 3. As shown, this hub has three circumferentially spaced spline teeth 60a, 60b, and 60c. These are defined by ballretaining overhanging tooth portions indicated at 60d, FIGURE 5, which serve to cage the balls 68, as hereinafter described.

The rotor 24' has an extending hub portion 62, FIG- URES l and 5. This hub portion, as in FIGURE 5, has a cavity portion 64 to receive telescopically the hub 60 of shaft 54 as shown in FIGURE 1. Internal teeth 66 of the cavity 64 extend inwardly to define mating spline conformations in relation to the spline teeth 60a, 60b, and 6th: of hub 60.

In the assembled condition, the hub 60 of shaft 54 is essentially co-axial with the hub 62 of rotor 24 and is received therein as shown in FIGURES l and 3. Balls 68 are received between the respective mating spline teeth 66 and 60a, 60b, and 60c. Drive engagement takes place, as shown in FIGURE 3, between the spline teeth 66 and 60a, 60b, and 600, through the medium of the balls 68.

Through the action of the above-described spline-like connection, the shaft 54 and the rotor 24 are connected in driving relation. It will be observed, however, that the balls 68 are effective to accommodate eccentricity and tilt between the axes of the shaft 54 and the rotor 2 as well as axial offset between shaft 54 and rotor 24.

The Vane Control Mechanism As is above explained, the respective vanes 28a, 28b, and 280 are held in fixed radial position to the rotor during the working stroke B, FIGURE 2, as shown by the vanes 28a and 28b. During their passage between shoes 2% and 22 the vanes are oriented in the nested circumferential position as shown by vane 230, FIGURE 2. Intermediate these two positions the vanes move in relation to the rotor as well as in relation to the housing 12.

This movement is effected by the crank elements indicated generally at 70, FIGURES 1, 3, and 5, and by the co- 8 operating cam track indicated at 72, FIGURES 1, 4, and 5.

The detailed construction of the crank arms will be evident from FIGURES -1, 3, and 4. As shown, each vane 28a, 28b, and 28c has a shaft portion 29a, 29b, and 290, the latter being shown in FIGURE 1. These shaft portions extend to the rotor proper, where they are received in suitable cylindrical bores defining sleeve bearings as shown. In the right hand direction of FIGURE 1 the shaft portions 29a, 29b and 29c protrude outside the shoulder portion 50 to receive the respective crank arms '70, as shown. As seen best in FIGURE 3, each crank arm 70 is defined by a segmental shaped arm 74 which is press fitted or otherwise secured to the shaft end. Each such arm 74 receives a roller 76 which is free to rotate about shaft 78 on the respective arm 74. As will be seen in FIGURE 1, each roller 76 is located outboard on the right hand side of the respective segmental arm on crank arm 70.

The rollers 76 are received in the cam track 72. This track is formed in the annular plate 88 which is snugly received in a corresponding recess on the left hand end of the output shaft housing 58. This plate is secured to the housing 58 by suitable studs 82, FIGURE 5.

In the form of the structure shown in FIGURES 1-9, inclusive, the crank arms 70 are oriented to position the rollers 76 at about a 35 degree offset in relation to the major axis of each vane and in the leading direction for the fluid flow shown. As shown in FIGURE 4, the cam track 72 has a portion of minor radius extending substantially about the working cavity B and a portion of major radius that spans the shoes 20 and 22; The portion of minor radius is indicated at 72a, FIGURES 4 and 5, and is of substantially uniform radius in relation to the axis 14-14. The value of this radius is that required to orient the vanes 28a, 28b, and 28c in the radial position. Accordingly, these vanes are of radial orientation and are held in radial orientation during the working stroke (the distance of about'120 degrees indicated at B, FIGURE 2).

The cam track portions of major radius indicated at 72b, FIGURES 4 and 5, are, for at least the extent of the shoes 20 and 22, of uniform radius in relation to axis 14. This radius is that orienting the vane in the circumferential or nested position. The vane 28c is shown in elevation in this position in FIGURE 3 as is the associated crank 70. The location of the cam track portion 72b for this vane position is shown in the dotted lines in FIG URE 4.

Intermediate the portions 72a and 72b, the cam track 72 is of smoothly varying conformation. In these regions, the cam track serves to swing each vane in relation to the rotor between the circumferential nested orientation and the radial Working orientation. It will be observed that for each full rotation of the rotor, each vane rotating crank 70 travels the full orbit of the cam track 72a. It thus swings from the inner to the outer position and returns upon each full rotor rotation. The vane thus does not have any net rotation upon a full rotor rotation, but rather returns to its initial position upon completion of each such rotation.

The Vane Construction The construction of the respective vanes 28a, 28b, and 280 is shown in enlarged view in FIGURES 6 to 9 inclusive. For purposes of discussion, only the vane 28c is shown, it being understood that the vanes are of identical construction. As shown, the shaft portions 290 of the vane 29 are formed as a unitary structure with the base portion 84. The base portion 84 is of rectangular shape forming one side of the completed vane. The opposite side of the completed vane is defined by the cap portion 36, FIGURES 7 and 8. Intermediate and sandwiched between the base 84 and the cap 86 there are a series of four seal plates indicated at 88, 90, 92, and 94, FIGURE 7. Each of these has a circular opening 88a, 99a, 92a, and 94a, FIGURE 7. Each such opening receives one of the circular spacers 96. These spacers in turn receive the rivets 98 which mount the cap portion 86 in spaced parallel relation to the base portion 84. The respective openings 88a, 99a, 92a, and 94a are each slightly larger in size than the spacers 96. This permits some movement of the respective seal plates 88, 90, 92, and 94 in relation to the base 84 and cap 86.

The seal plate 88 is shown in perspective view in FIG- URE 9. It is of generally right triangle conformation with the right angle sides indicated at 88b and 880. The apices opposite the 90 degree apex are cut ofi and, in addition, the face of the seal plate is cut oflf on its top side at 88d and 882.

The seal plates 90, 92, and 94 are of shape similar to seal plate 88. As will be seen in FIGURE 7, seal plate 92 is rotated one-half turn in relation to the orientation of plate 88 and is on the opposite corner of the vane. Also, as will be evident from FIGURE 7, the seal plate 94 is inverted in relation to seal plate 88 and is located on the adjacent corner. Similarly seal plate 90 is inverted in relation to seal plate 88 and is located on an adjacent corner. The resulting disposition of the seal plates provides a seal extending entirely around the vane. This seal may be traced along the top edge as seen in FIGURE 7 from the seal plate 88 to the cut-oif portion 88d of seal plate 88 thereof and thence to the corresponding cut-off portion 90d of seal plate 90. The edge can be traced further along the top edge of the vane as seen in FIG- URE 7. In the overlapping region of portions 88d and 90d there is always at least one of the seal plates effective to define a seal surface. The sealing surface may similarly be traced over the other three sides of the vane.

FIGURES 6 and 8 show in side elevation and in perspective, respectively, how the portions 92d and 94d of the seal plates 92 and 94 overlap to define a complete seal. It will be evident that the other overlapping portions of the seal plates similarly overlap to form an effective seal.

The compressed spring ring 98 is located in the rectangular space formed by the lengthy edges of the respective seal plates as is shown in FIGURE 7. This ring urges the seal plates outwardly. In the assembled fluid displacement device, the movement of the respective seal plates is arrested by the operating surfaces with which they come in contact, particularly the inner face 16 and the outer face 18 of the working chamber B, FIG- URE 2, and the sides of the rotor engaged by the vanes.

The Alternative Embodiment of FIGURES 10-15 FIGURES 10-15 show an alternative embodiment of the structure of FIGURES 1-9, inclusive. Parts corresponding to those of FIGURES l-9 are shown by like reference numerals with 100 added. Unless otherwise herein indicated, the construction of FIGURES 10-14 is like that of FIGURES 1-9. The features of the construction of FIGURES 10-15, or selected ones of them, may be incorporated in the FIGURES 1-9 structure as desired.

In FIGURES 10 and 11, an alternative form of the vane structure is shown. The specific vane illustrated is vane 1280, FIGURE 14. It will be understood that the other two vanes of FIGURE 14 (128a and 1281)) are of like construction. In this vane construction, the outboard shaft portions 1290, the base portion 184, and the cap portion 186, together with a web portion 185 forming a continuation of the outboard shaft portions 1290, are formed of a single piece of material. This defines oppositely disposed slots 183 which are adapted to receive and, in use do receive, the Teflon seal inserts 192, one of which is shown in exploded relation to the slot 183 in FIGURE 10.

The Teflon seals 192 are of rectangular cross-section adapted to fit snugly in the slots 183. A pair of longitudinal slots 192a are cut along the opposite faces of the seals as shown in FIGURES l and a. These slots are of about 0.015 inch width and each extends from one face of the seal almost to the opposite face. In an actual unit, the slots extended about two-thirds across the seals and are spaced about 0.03 inch. They thus define thin, relatively flexible sections 19% on the opposite faces of the seal, together with a relatively long intermediate section 1920. As shown, the slots 192a are located adjacent the outer face of the seal, but within the confines of the slots 183.

The intermediate section 192c between the slots 192a is flexed in beam action upon application of compressing force to the seal 192. The resulting bending moment applied to this section and to the thin relatively flexible sections 192b on the opposite faces of the seal gives rise to relatively free flexing action of the seal 192. The seals 192 are of size to protrude slightly beyond the confines of the vane when in relaxed condition. They likewise protrude beyond the radial width of the working portion B, FIGURE 2, of the cavity formed in the housing 12. The seals are accordingly compressed to wipe along the surface of the working portion B and define an effective fluid seal.

The seals 192 are secured in the respective vanes by set screws 193 which are received in bores 1922 in the seals 192 and are threadedly received in the threaded inner portions of the bores 195 and have end portions (not shown) that bear against the faces of the seals 192 at points inboard the slots 192a.

In the modified construction of the rotor 24 and the housing 12 shown on FIGURE 12, a ball bearing 153 is located in the position of the seal 53, FIGURE 1, thus providing a ball bearing support for the left hand end of the rotor 124 as seen in FIGURE 12. Since the ball bearing provides a positive support involving no sliding metal surfaces, this construction has the advantage of locating the rotor in centered position while at the same time providing minimum friction. The seal 153a, preferably of Teflon, bears against the inner cylindrical surface 144a of the rotor 124 to provide a seal against fluid leakage from the working chamber in the left hand direction as seen in the figure.

In the construction of FIGURE 12, a ball bearing 152a is located at the right hand end of the rotor 124. The inner race of this hearing seats on shoulder 15012 of the rotor. The outer race seats on the inner cylindrical surface 1120 formed on the housing 112 as shown. The rotor 124 is thus located in axially centered location by the bearings 152a and 153 and no wiping metallic surfaces are relied upon to hold the rotor in axial position.

FIGURE 13 is a view in perspective showing a modified construction of the shoes 20 and 22, FIGURE 2, to provide additional seal elements. As shown, the shoe has four slots 120a. Similarly, the shoe 122 has four slots 122a. These slots each receive an insert of Teflon or similar resiliently deformable material as indicated at 121 and 123 of the broken away portions of FIGURE 15. It will be noted that the slots 120a and 122a are sufficiently deep to extend below the level of engagement between the respective flange portions 144, 146, 148, and 150 of the rotor and the shoes. The outboard slots 120a and 122a are spaced sufiiciently to span the rotor vane windows 126a, 126b, and 126c. Each pair of adjacent slots 129a and 122a is spaced sufiiciently close to be spanned by the rotor sleeve portions between each window 126a, 126b, and 126a and the adjacent windows 142. The seals thus define a non-metallic sealing engagement entirely about each shoe which at all times defines at least one seal.

FIGURE 14 is a view in perspective of the rotor of the construction of FIGURES 10-15, with the end part 145, FIGURE 12, removed. As shown, the rotor has a sleevelike portion 124 with three equally spaced windows in which the respective vanes 128a, 128b, and 1280 are received. The protruding end shaft portions 129a, 129b, and 129c of these vanes are received in appropriate sleeve bearing portions of the end part in the manner shown at 290, FIGURE 1. The respective vanes are received in similar sleeve bearing portions of the end flange part 1 1 150-148, as is likewise shown at 290, FIGURE 1. The roller 176 of the crank arm mechanism for the vane 1281) is also shown in FIGURE 14.

In the embodiment of FIGURES -15, the communicating channels 157 extending from the left hand face of the rotor as seen in FIGURE 12 to the right hand face register with the respective auxiliary windows 142, FIG- URE 14, of the rotor.

Assembly The parts of the units of FIGURES l-9 and FIGURES 10-15, are secured together as follows. The rotor unit consists of two main parts. One is the structure shown in FIGURE 14. The other is the annular part 145, FIG- URE 12, which is located adjacent the closed end of the cavity before the shoes are secured in position. As shown in FIGURE 14, the sleeve portion 124 of the rotor (24, FIGURE 1) defines an annular face 151 having a series of threaded bolt-receiving openings 147a. These register with countersunk bores 14711 in the end plate 145, which defines the flange portions 144 and 146. Suitable studs (not shown) are received in recessed relation in the bores 1471) and are threadedly received in the openings 147a to secure the plate 145 in position and thereby complete the rotor assembly. Openings are provided in proper positions in the closed end of the housing 112 to receive the securing bolts and to permit them to be rotated to tight position. One such opening is shown at 143, FIG- URE 12. When the rotor is assembled, these openings are closed, as by screw 141, FIGURE 12.

With the rotor thus assembled and placed within the housing 12, the right end cap assembly 58, FIGURE 5, may now be placed in position. To this end, the balls 63 (168, FIGURE 12) are laid in and the end cap assembly inserted (with the vanes oriented to place the cam followers 76 (FIGURE 3) and 176 (FIGURE 14) in the cam track 72 (FIGURE 1) and 172 (FIGURE 12)). The assembly is completed by securing mounting bolts (not shown) which extend through the respective bores 99, FIGURE 5, in the end cap 58 and are threadedly received in the mating threaded bores 97 of the housing 12.

It will be observed from the foregoing description that the fluid travels into the housing 12 through a straight passage defined by pipe 36 and inlet chamber 30. The fluid leaves by a similar straight passage defined by the outlet chamber 34 and the outlet pipe 38. Intermediate these passages, the fluid makes a full turn within the work ing chamber B, FIGURE 2, during most of which time the fluid is effective in working action in relation to the vanes. The fluid path thus defined is highly favorable for effective working action, while at the same time the fluid is not subjected to undesirable changes in direction having no value in terms of producing mechanical work or in pumping action.

It will be also observed that the intermediate windows 42 in the rotor provide for the free passage of the working fluid between the inlet and outlet passages 30 and 34 and the inner annular portion of the working chamber B. As shown by the arrows in FIGURE 2, the working fluid passes through these windows to reach the annular space between post 17 and the sleeve portion 24 of the rotor and is not required to make the rather sharp (and hence lossproducing) turn adjacent each vane that would otherwise be necessary to travel between the space outside the sleeve portion of the rotor and the space within the same.

The space between the poster hub 17 and the inner face 23 of the sleeve part 24 of the rotor provides an additional working surface for application of fluid pres sure to each vane during the working stroke. It thus serves to increase the amount of fluid displaced upon each rotor rotation and, consequently, the pumping capacity in pump action and horsepower output in motor action. In addition, the area thus exposed to the fluid pressure defines a completely balanced surface against which the fluid acts on each vane. The fluid pressure thus does not tend to rotate the vane during the working stroke. It is 12 thus unnecessary to design the vane supporting elements to withstand substantial unbalanced fluid pressure.

The shoes 21 and 22 span a circumferential distance along the sleeve part 24 of the rotor that exceeds the circumferential extent of the windows 26a, 26b, and 250. If desired, the shoes may be relieved intermediate their edge portions since the essential sealing is required only at points spaced more than the circumferential extent of these windows. With the shoe arrangement of FIG- URES 13 and 15, where the shoes have sealing elements 121 and 123, the sealing elements are spaced circumferentially of the sleeve part of the rotor by a distance exceeding the circumferential extent of the windows of the rotor.

During operation of the devices herein described, the vanes 28a, 25b, and 23c (and the vanes 128a, 12811, and 128a) undergo two types of movement. One type of movement is about the axis of the vane itself. This movement is controlled by the action of the crank elements 70 (and 170). The other movement is about the axis of the rotor and is due to the rotor rotations. The former movement is essentially absent during the working stroke B and during the time the respective vanes pass between the stator shoes 20 and 22 (or and 122). When each vane is being rotated to circumferential position after concluding the working stroke, the movement of the rotor tends to aid in the necessary movement of the vanes, so that the required vane movement about its own axis is less than the quarter turn otherwise required. When each vane is being rotated from circumferential position to radial position to begin the working stroke, the rotor movement tends to increase the necessary movement of the vane about its own axis. The resulting movement is accordingly more than a quarter turn.

In an actual fluid displacement device constructed as shown in FIGURES 1 to 9, operation as a pump was carried on up to 2000 rpm. This was the limit of the available mechanical drive capacity for driving the unit. At this speed there was no indication that the limit of possible rotor speed was being approached. The pump volumetric output was essentially in proportion to speed. The outer diameter of the rotor sleeve part 24, FIGURE 2, was about 2.5 inches. Other parts were in essentially the proportions of FIGURES 19, inclusive.

With the foregoing construction, the radius of the cylin cler defined by the vane bearing axes as elements was one and one sixteenth inches and the active area of each vane was about 0.375 square inches. Calculated horsepower at 1000 pounds per square inch pressure differential and 2000 rpm. was about 12 horsepower.

The constructions herein described are characterized by an ability to accommodate the use of resilient seals to effect fluid seal action where it is not desired to do so by metal-to-metal surfaces. As above described, such seals can be used in positions where they are sandwiched between metallic supporting surfaces. It is thus possible to use a sealing material that is incapable of withstanding the fluid pressure (except in a stubby portion protruding from the metallic supporting structure) and is characterized by relatively easy flexibility that assures a fluid tight seal. This is in contrast to some of the constructions of the prior art, which have not permitted such seal application and, consequently have demanded reliance upon metal-to-metal sealing arrangements with the incident close fits, wear, and other disadvantages.

As examples of the supported sealing structures thus made possible, attention may be directed to the seals 1532, FIGURE 10, the seals 121 and 123, FIGURE 15, the seals 52 and 152, FIGURES l and 14, the seals 153a, 151, and 149, FIGURE 12, and others. It should be particularly noted that all of the seals may be made in this fashion and all metal-to-metal seals avoided.

As described above, the seal material herein preferred is Teflon. This is a tetrafluoroethylene polymer that may be molded, and if necessary, machined to shape. See Pat- 13: outs 2,230,654, 2,394,243, 2,393,967 and 2,534,058. It is characterized by inertness to hydraulic oil, a very low co-efficient of friction against the metal surfaces (particularly in the presence of the hydraulic oil), relatively easy expansion and contraction, and relatively good tensile, shear, and compressive strength.

In the construction herein described, the force of the unbalanced fluid pressure acting on the vanes during the working stroke is balanced by a like force developed by the bearing support for the rotor to produce the torque effective on the rotor. Since the balancing force developed by the rotor bearing support contains no thrust component, it is of a nature that is relatively easily withstood by the rotor bearing supports. If desired, the rotor bearing load thus developed can be reduced greatly by coupling two like fluid displacement devices with their rotors connected and supported by a common bearing support. With the working portions B of the two units in diametral opposition, the vanes themselves develop the torque without reaction on the bearing supports.

The vanes in the device herein described rock back and forth in relation to the sleeve-like rotor without undergoing any full rotations in relation to the same. By virtue of this vane movement it is possible to guide the vanes in their necessary travel by a single cam track 72, FIG- URE 1 (172, FIGURE 12). Moreover, this arrangement makes it possible to utilize a cam track of relatively simple conformation. It need only be of appropriate radius at the working stroke (B, FIGURE 2) to orient the vanes radially and of appropriate radius in the region adjacent the shoes to tuck the vanes within the confines of the rotor, and of shape to provide a smooth vane movement therebetween. Gears, with the incident cost and noise, and double cam traces with the incident complexity and expense are avoided.

The structure of FIGURE '12, with bearings 153 and 152a is preferred over that of FIGURE 1. It has been found that in a structure like FIGURE 1 the radial load placed on the Teflon seals (serving as bearings) is suflicient to cause undesirable wear and tendency to jam. The bearings 153 and 152a, with their greater ability to withstand this load, have been found superior in this respect.

It has further been found that the coupling elements defined by spline-like unit 60, FIGURE 5, and the cooperating socket 64, FIGURE 5, are preferably supplemented by an external coupling that permits further misalignment between the drive or driven shaft and shaft 54, FIGURE 1. If desired, the elements 6044 may define a simple spline and the external coupling used as the sole means to accommodate eccentricity.

It will be noted from FIGURE 2 that the working chamber B is the bottleneck or principal obstruction for fluid flow between the inlet and outlet chambers. This aids in providing favorable efficiency.

In some of the appended claims the vanes are defined as nesting or tucking within the confines of the rotor when in circumferential position. The inner and outer diameters of the rotor sleeve define an annulus in section as shown, for example, in FIGURE 2. The vanes (28a, 28b, 28c, FIGURE 2) nest or tuck within this annulus in that they are within the space between the inner and outer rotor diameters when in circumferential orientation, and thus pass between the shoes (20 and 22, FIGURE 2) without interference.

While we have shown for purposes of illustration specific forms of the fluid displacement device constructed in accordance with the present invention, it will be understood that numerous variations and alternative constructions may be made without departing from the true spirit claims to cover all such modifications and alternative constructions falling within their true spirit and scope.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A fluid displacement device comprising in combination: a housing defining an annular cavity having an axis and inner and outer cylindrical faces of predetermined annular spacing, said housing further defining angularly spaced fluid inlet and outlet passages to the cavity and forming extensions of tangents to diametrically opposed points on the cavity to define a U-shaped flow path through substantially one-half of the cavity; a sleeve-like rotor disposed within the cavity, extending the axial length thereof, having its axis coaxial with the axis of the cavity, and rotatably supported in relation to the housing; a pair of complementary shoes aflixed to the inner and outer faces of the cavity, respectively, and extending to fluid tight spacing in relation to the rotor, the shoes being located between the inlet and outlet passages and defining fluid sealing surfaces spaced circumferentially by distance at least equal to the annular spacing of said faces, the rotor having at least three windows extending the axial length of the cavity and located at predetermined equal angular spacings; vanes located in the windows, respectively, and swingable about axes parallel to the axis of the rotor, each vane being adapted in a radial position to establish a fluid seal across the cavity and in a circumferential position to nest within the confines of the rotor; the rotor further having windows intermediate said first windows for fluid entrance to and exit from the inner space formed by the cavity and rotor; and means operative to hold each vane in fixed radial position for rotor rotation at least encompassing said predetermined angular spacing opposite to the shoes to effect working stroke, to orient the vanes in circumferential nesting position in relation to the rotor to pass between the shoes and to rotate the vanes between said positions during intermediate travel thereof, the circumferential length of the shoes being substantially less than the circumferential spacings of the vanes.

2. A fluid displacement device comprising in combination: a housing defining an annular cavity having an axis and inner and outer cylindrical faces of predetermined annular spacing, said housing further defining angularly spaced fluid inlet and outlet passages to the cavity and forming extensions of tangents to diametrically opposed points on the cavity to define a U-shaped flow path through substantially one-half of the cavity; a sleeve-like rotor disposed within the cavity, extending the axial length thereof, having its axis coaxial with the axis of the cavity, and rotatably supported in relation to the housing; a pair of complementary shoes affixed to the inner and outer faces of the cavity, respectively, and extending to fluid tight spacing in relation to the rotor, the shoes being located between the inlet and outlet passages and defining fluid sealing surfaces spaced circumferentially by distance at least equal to the annular spacing of said faces, the rotor having at least three windows extending the axial length of the cavity and located at predetermined equal angular spacings; vanes located in the windows, respectively, and swingable about axes parallel to the axis of the rotor, each vane being adapted in a radial position to establish a fluid seal across the cavity and in a circumferential position to nest within the confines of the rotor; the rotor further having windows intermediate said first windows for fluid entrance to and exit from the inner space formed by the cavity and rotor; crank arm elements attached to the vanes, respectively, and defining cam followers outboard the same; and means defining a fixed cam track receiving said cam followers the track defining a path to orient the vanes radially at least through said predetermined angular spacing opposite the shoes to effect working stroke and in relation to the rotor to pass between the shoes and to rotate the vanes between said positions during intermediate travel thereof, the circumferential length of the shoes being substantially less than the circumferential spacings of the adjacent ends of the vanes when circumferentially oriented.

3. A fluid displacement device comprising in combinaa,125,'se2

tion: a unitary housing defining an annular chamber open on one side, having a central cylindrical post of substantially uniform diameter along its length, a pair of complementary shoes extending from the inner and outer faces of the chamber to define a secondary arcuate passage coaxial with the annular chamber, and fluid inlet and outlet openings located respectively on opposite sides of the shoes; a sleeve-like rotor unit in the chamber and axially slidable thereinto, said rotor unit having a sleeve part fitting snugly in the secondary arcuate passage and vanes adapted to tuck within said sleeve part when circurferentially oriented and to seal the annular chamber in a working portion opposite the shoes when radially oriented, the portions of the rotor between adjacent ends of the vanes when in circumferential position being of suflicient circumferential extent to obstruct fluid fiow between the inlet and outlet openings and the space inside the sleeve part, said rotor further having windows intermediate the vanes; and end cap elements closing the open face of the cavity to define an enclosed structure, said vanes having cam follower guide parts extending outboard the rotor unit and said end cap elements including cam-track defining elements adapted to receive said guide parts when in position.

4. An improved fluid displacement device comprising in combination: a unitary housing defining an annular chamber having an axis and substantially uniform inner and outer diameters, said chamber being open on one side and closed on the other side; a pair of complementary shoes extending from the inner and outer faces of the chamber in spaced relation to the closed side to define a secondary arcuate passage coaxial with the annular chamber; a two-part rotor located within said chamber, one part of the rotor being of annular conformation and located between said shoes and the closed side of the chamber and in sealing relationthereto, and the other part being of sleeve-like conformation adapted to fit snugly in the secondary arcuate passage and having vanes adapted to pass through said passage when in circumferential position and to seal the annular chamber in a working portion opposite the shoes when radially oriented; said one part of the rotor defining bearing portions adapted to receive the vanes, respectively; means accessible through the closed side of the housing after assembly of the rotor parts within the housing to secure the same together, thereby forming a spool-like unit straddling the shoes, the rotor parts defining fluid balance passages extending through said other part of the rotor between opposite sides thereof to relieve unbalanced fluid pressures; means to swing the vanes to radial positions for working stroke and to circumferential positions to pass through the secondary annular passage; and end cap elements closing the open face of the cavity to define an enclosed structure.

5. An improved fluid displacment device comprising in combination: a unitary housing defining an annular chamber having an axis and substantially uniform inner and outer diameters, said chamber being open on one side and closed on the other side; a pair of complementary shoes extending from the inner and outer faces of the chamber in spaced relation to the closed side to define a secondary arcuate passage coaxial with the annular chamber; a two-part rotor located within 'said chamber, one part of the rotor being of annular conformation and located between said shoes and the closed side of the chamber in sealing relation thereto, and the other part being of sleeve-like conformation adapted to fit snugly on the secondary arcuate passage, having vanes adapted to pass through said passage when in circumferential position and to seal the annular chamber in a working portion opposite the shoes when radially oriented, said other part further having flange portions adjacent said sleevelike conformation and spanning said annular chamber in sealing relation thereto; means accessible through the closed side of the housing after assembly of the rotor parts within the housing to secure the same together, thereby l. 3 forming a spool-like unit straddling the shoes, the rotor parts defining fluid balance passages extending through said other part of the rotor between opposite sides thereof to relieve unbalanced fluid pressures; and end cap elements closing the open face of the cavity to define an enclosed structure, said end cap elements defining a cam track and the said vanes having cam followers received in said track to swing the vanes to radial positions for working stroke and to circumferential positions to pass through the secondary annular passage.

6. An improved fluid displacement device comprising in combination: a unitary housing defining an annular chamber having an axis and substantially uniform inner and outer diameters, said chamber being open on one side and closed on the other side; a pair of complementary shoes extending from the inner and outer faces of the chamber in spaced relation to the closed side to de fine a secondary arcuate passage coaxial with the annular chamber; a two-part rotor located within said chamber, one part of the rotor being of annular conformation and located between said shoes and the closed side of the chamber in sealing relation thereto, and the other part being of sleeve-like conformation adapted to fit snugly in the secondary arcuate passage, having vanes adapted to pass through said passage when in circumferential position and to seal the annular chamber in a working portion opposite the shoes when radially oriented, the vanes having a major axis of shorter extent than the circumferential span of the shoes, said other part further having flange portions adjacent said sleeve-like conformation and spanning said annular chamber in sealing reation thereto; means accessible through the closed side of the housing after assembly of the rotor parts within the housing to secure the same together, thereby forming a spool-like unit straddling the shoes, the rotor parts defining fluid balance passages extending through said other part of the rotor between opposite sides thereof to relieve unbalanced fluid pressures; and end cap elements closing the open face of the cavity to define an enclosed structure, said end cap elements defining a cam track and the said vanes having cam followers received in said track to swing the vanes to radial positions for working stroke and to circumferential positions to pass through the secondary annular passage.

7. A fluid displacement device comprising in combination: a housing defining an annular chamber open on one side, having a central cylindrical post of substantially uniform diameter along its length, defining a fluid inlet and outlet openings tangentially oriented in relation to said chamber and having spaced substantially by the diameter of the post to define a U-shaped flow path through substantially half of the chamber, and a pair of complementary shoes extending from the inner and outer faces of the chamber in the region between said inlet and outlet openings and substantially spanning the circumferential length of the chamber therebetween to define a secondary arcuate passage coaxial with the annular chamber, the spacing between the adjacent edges of said openings being slightly greater than the distance between the inner and outer diameters of the chamber; a sleevelike rotor unit in the chamber and axially slidable thereinto, said rotor unit having a sleeve part fitting snugly in the secondary arcuate space, three vane-receiving windows having their centers spaced degrees and of circumferential extent less than said circumferential spacing between said openings, vanes in said windows, respectively, adapted to tuck within said sleeve part when circumferentially oriented and to seal the annular chamber in a working portion opposite the shoes when radially oriented, the sleeve part further defining end faces in an annular conformation in planes normal to the axis, said sleeve part further having windows located between said first windows and of less circumferential extent than said spacing between said openings and ring members affixed to the sleeve-like rotor unit at the end faces thereof to 1 7 define a rugged unitary spool-like structure; and end cap elements closing the open face of the cavity to define an enclosed structure, said vanes having cam follower guide parts extending radially outboard the rotor unit, and said end cap elements including cam-track defining elements adapted to receive said guide parts when in position.

8. A vane unit for a fluid displacement device comprising, in combination: means defining a pair of spaced trunnions on an axis and a rectangular vane body therebetween, the vane body having two spaced portions in planes parallel to the axis and to each other and straddling the axis in spaced relation to form a slot adapted to receive a flexible seal; and four movable seal elements located in said slot, said elements defining rectangular corners, the corners of the seal elements being located in the corners of the vane body, respectively, the seal elements having overlapping edge portions inboard the corners spanning the edges of the vanes, the seal elements further having edges inboard the corners defining a generally rectangular interior space; and a central resilient expansion ring disposed in said interior space and bear- 18 ing against the seal elements, respectively, to urge the same to outward sealing positions.

References Cited in the file of this patent UNITED STATES PATENTS 1,101,329 Reaugh June 23, 1914 2,009,137 Kleckner July 23, 1935 2,049,797 Bochmann Aug. 4, 1936 2,605,714 Hoenecke Aug. 5, 1952 2,619,913 Longenecker Dec. 2, 1952 2,750,214 Bermingham June 12, 1956 2,874,982 Winther Feb. 24, 1959 2,896,545 Brulle July 28, 1959 FOREIGN PATENTS 265,576 Great Britain Aug. 4, 1927 290,044 Germany Feb. 3, 1916 344,514 Switzerland Mar. 31, 1960 480,159 Germany July 27, 1929 614,326 Great Britain Dec. 14, 1948 

1. A FLUID DISPLACEMENT DEVICE COMPRISING IN COMBINATION: A HOUSING DEFINING AN ANNULAR CAVITY HAVING AN AXIS AND INNER AND OUTER CYLINDRICAL FACES OF PREDETERMINED ANNULAR SPACING, SAID HOUSING FURTHER DEFINING ANGULARLY SPACED FLUID INLET AND OUTLET PASSAGES TO THE CAVITY AND FORMING EXTENSIONS OF TANGENTS TO DIAMETRICALLY OPPOSED POINTS ON THE CAVITY TO DEFINE A U-SHAPED FLOW PATH THROUGH SUBSTANTIALLY ONE-HALF OF THE CAVITY; A SLEEVE-LIKE ROTOR DISPOSED WITHIN THE CAVITY, EXTENDING THE AXIAL LENGTH THEREOF, HAVING ITS AXIS COAXIAL WITH THE AXIS OF THE CAVITY, AND ROTATABLY SUPPORTED IN RELATION TO THE HOUSING; A PAIR OF COMPLEMENTARY SHOES AFFIXED TO THE INNER AND OUTER FACES OF THE CAVITY, RESPECTIVELY, AND EXTENDING TO FLUID TIGHT SPACING IN RELATION TO THE ROTOR, THE SHOES BEING LOCATED BETWEEN THE INLET AND OUTLET PASSAGES AND DEFINING FLUID SEALING SURFACES SPACED CIRCUMFERENTIALLY BY DISTANCE AT LEAST EQUAL TO THE ANNULAR SPACING OF SAID FACES, THE ROTOR HAVING AT LEAST THREE WINDOWS EXTENDING THE AXIAL LENGTH OF THE CAVITY AND LOCATED AT PREDETERMINED EQUAL ANGULAR SPACINGS; VANES LOCATED IN THE WINDOWS, RESPECTIVELY, AND SWINGABLE ABOUT AXES PARALLEL TO THE AXIS OF THE ROTOR, EACH VANE BEING ADAPTED IN A RADIAL POSITION TO ESTABLISH A FLUID SEAL ACROSS THE CAVITY AND IN A CIRCUMFERENTIAL POSITION TO NEST WITHIN THE CONFINES OF THE ROTOR; THE ROTOR FURTHER HAVING WINDOWS INTERMEDIATE SAID FIRST WINDOWS FOR FLUID ENTRANCE TO AND EXIT FROM THE INNER SPACE FORMED BY THE CAVITY AND ROTOR; AND MEANS OPERATIVE TO HOLD EACH VANE IN FIXED RADIAL POSITION FOR ROTOR ROTATION AT LEAST ENCOMPASSING SAID PREDETERMINED ANGULAR SPACING OPPOSITE TO THE SHOES TO EFFECT WORKING STROKE, TO ORIENT THE VANES IN CIRCUMFERENTIAL NESTING POSITION IN RELATION TO THE ROTOR TO PASS BETWEEN THE SHOES AND TO ROTATE THE VANES BETWEEN SAID POSITIONS DURING INTERMEDIATE TRAVEL THEREOF, THE CIRCUMFERENTIAL LENGTH OF THE SHOES BEING SUBSTANTIALLY LESS THAN THE CIRCUMFERENTIAL SPACINGS OF THE VANES. 